Management of sleep-related breathing disorders in children

Chapter 63 Management of sleep-related breathing disorders in children

David H. Darrow, Kaalan E. Johnson

1 INTRODUCTION

Sleep-related breathing disorders (SRBD) are a common occurrence in children. While such events may be central in etiology, most affected children experience obstructive sleep disorders, caused by anatomic variations and complicated by the diminished pharyngeal muscle tone and neurophysiologic changes that typically accompany sleep. Hyperplasia of the tonsils and adenoid is the most common cause of such obstruction, but infants and toddlers may be affected at a variety of sites in the upper respiratory tract. Causes of SRBD in children may be grouped on the basis of age, simplifying the differential diagnosis for a given patient (Table 63.1). In small children, caliber of the airway may be reduced due to nasal obstruction, compromised skeletal anatomy, hyperplastic pharyngeal or laryngeal soft tissues or neuromuscular compromise. In addition, in older children, obstruction due to obesity has been encountered with increasing frequency over the last two decades.1,2

Table 63.1 Causes of sleep-related breathing disorders in children

Neonates and infants
Nasal aplasia, stenosis, or atresia
Nasal or nasopharyngeal masses
Craniofacial anomalies:
Hypoplastic mandible (Pierre Robin, Nager’s, Treacher Collins)
Hypoplastic maxilla (Apert’s, Crouzon’s)
Macroglossia (Beckwith–Wiedemann)
Vascular malformations of tongue and pharynx
Congenital cysts of the vallecula and tongue
Neuromuscular disorders
Toddlers and older children
Rhinitis, nasal polyposis, septal deviation
Syndromic narrowing of nasopharynx (Hunter’s, Hurler’s, Down’s, achondroplasia)
Adenotonsillar hyperplasia
Obesity
Macroglossia (Down’s)
Vascular malformations of tongue and pharynx
Neuromuscular disorders
Iatrogenic
Nasopharyngeal stenosis

Successful management of SRBD in children depends on accurate identification of the site of obstruction and assessment of the severity of obstruction. Only then can appropriate surgical and non-surgical remedies be considered.

2 DIAGNOSIS OF SRBD IN CHILDREN

In most children with SRBD, the presenting symptom is stertor, a term used to describe sonorous breathing in the upper airways, including snoring. The prevalence of snoring during sleep has been reported as 3–12% in children,3 although some studies suggest the rate may be as high as 27%.4 Primary snoring is generally not considered a form of SRBD, although some studies do suggest the possibility of associated morbidity such as elevated blood pressure and reduced arterial distensibility.5

In its mildest form, SRBD presents as upper airway resistance syndrome (UARS). Affected children demonstrate episodic arousals resulting from partial obstruction of the upper airway, associated with symptoms of heroic snoring, mouth-breathing, sleep pauses or breath-holding, gasping, perspiration, and enuresis. Daytime manifestations of sleep disturbance include morning headache, dry mouth, halitosis, and most significantly behavioral and neurocognitive disorders.6 Hypersomnolence may occur in older children and adolescents. Other signs and symptoms include audible breathing with open mouth posture, hyponasal speech, and chronic nasal obstruction with or without rhinorrhea. Approximately 40% of children who snore demonstrate more significant degrees of obstruction characteristic of obstructive hypopnea syndrome (OHS) or obstructive sleep apnea syndrome (OSAS) as defined below.6 The most severely affected patients may develop cor pulmonale, right ventricular hypertrophy, congestive heart failure, alveolar hypoventilation, pulmonary hypertension, pulmonary edema, or failure to thrive, and are at risk for permanent neurological damage and even death.

Physical examination is critical in establishing the site of obstruction and will ultimately determine the most appropriate surgical intervention. The examination should include assessment of the patient’s weight and body habitus, a complete examination of the head and neck with attention to potential sites of obstruction, and auscultation of the patient’s heart and lungs. Friedman tongue position (FTP), described in Chapter 16 on clinical staging, should be assessed. Children with FTP III or IV have significant retrolingual obstruction in addition to possible tonsillar and adenoid obstruction. Postoperative PSL and follow-up is essential in those patients since they are likely to have residual or recurrent OSAHS after tonsillectomy and adenoidectomy. Findings of nasal dyspnea or mouth-breathing, hyponasal speech, mandibular hypoplasia, drooling, neuromuscular deficit, and tonsillar hyperplasia all suggest some degree of upper airway obstruction. In many cases, such as infants in whom the jaw is extremely micrognathic or toddlers in whom the tonsils are massively enlarged, office examination alone may suffice. Ancillary studies such as high kilovoltage radiography of the adenoid pad and/or lingual tonsils and direct fiberoptic assessment of the nasal vault, adenoid pad, and distal pharynx and larynx may be useful in selected cases. In severely obstructed children, chest radiography and electrocardiography should be considered as well. In cases of nasal obstruction in infants and young children, CT scanning may be desirable in order to define the bony anatomy and to assess the relationship of nasal masses to the sinonasal tract and the central nervous system. At some institutions, cross-table lateral fluoroscopy, drug-induced sleep endoscopy, or cine MRI may be performed during sleep to aid in localizing the site of obstruction.

When a history of severe symptoms of sleep disturbance correlates with obvious physical findings of airway obstruction, additional studies to establish a patient’s candidacy for surgical intervention may be superfluous. However, studies suggest that in most cases accurate diagnosis of SRBD cannot be established solely on the basis of a history and physical examination.7 SRBD occurs primarily during REM sleep when children are less likely to be observed by their parents,8 and in many cases of UARS and OHS parents may misinterpret the symptoms only as snoring in the absence of obstruction. In addition, airway dynamics during sleep cannot be determined by static examination in the office setting, and fiberoptic assessment of the airway is often deceptive due to the distorted wide-angle view. Similarly, radiographic assessment of the adenoid tissue and tongue base may be difficult to interpret. In such cases, polysomnography (PSG) remains the gold standard for objective correlation of ventilatory abnormalities with sleep disordered breathing.7 However, the severity of obstruction for which intervention is recommended remains controversial, with most authors advocating aggressive management of children whose Respiratory Distress Index (RDI; obstructive apneas+hypopneas per hour) is between 1 and 5. Furthermore, the expense and scheduling difficulties associated with PSG make this a cumbersome method of assessment in many otolaryngology practices. Other techniques of assessment including audiotaping, videotaping, and home and abbreviated PSG have demonstrated favorable results, but require further study.

3 MANAGEMENT OF SRBD IN CHILDREN

3.1 NON-SURGICAL MANAGEMENT

Treatment of SRBD in children is tailored to the etiology of the airway obstruction. Medical management, such as thioxanthines and methylphenidate, may be useful in cases of central apnea. Pharmacotherapy may also be considered in less severe cases of obstructive apnea, or when surgical intervention does not address the pathology. Examples of such disorders include neonatal rhinitis, allergic rhinitis, and acute tonsillitis. Systemic steroids are effective in reducing lymphoid hyperplasia, but the results are often transient. In cases of chronic upper airway obstruction, positive airway pressure has demonstrated high efficacy in treating SRBD in children; however, the dropout rate is high and the rate and duration of nightly use are relatively low even among compliant children.9 Other alternatives, such as mechanical correction by prostheses, orthodontia, or weight loss, may be worth consideration as well, although these interventions are rarely tolerated in children and are often ineffective. As a result, even in cases of SRBD due to obesity and neuromuscular impairment, surgical management is generally considered as first-line therapy and other modalities are entertained postoperatively to address residual obstruction.

3.2 SURGICAL MANAGEMENT

3.2.1 PREOPERATIVE PLANNING

Preoperative planning is an essential component of the surgical management of patients with SRBD. Such individuals are prone to airway embarrassment during induction of anesthesia, and the surgeon and anesthetist should discuss emergency intervention for the airway should the patient become acutely obstructed. In most cases, dynamic airway collapse may be overcome by bag/mask ventilation used with an oral airway. In patients with severe micrognathia, macroglossia, or lingual tonsil hyperplasia, visualization of the larynx may be compromised. In such cases, the operating team should preoperatively assemble those items necessary for intubation with a Bullard laryngoscope, flexible fiberoptic bronchoscope, or fiberoptic intubation wand, and patients should be intubated under conditions of maximal topical and minimal systemic anesthesia, preferably in the sitting position.

Postoperative respiratory distress is common after surgery for SRBD due to effects of anesthesia, bleeding, edema, and residual airway compromise. Patients at greatest risk include those with severe OSAS, diminished neuromuscular tone (i.e. cerebral palsy), morbid obesity, skeletal and craniofacial abnormalities such as hypoplasia of the midface and/or mandible or nasopharyngeal vault, and very young children (under age 2–3).10,11 As a result, high-risk individuals who are undergoing even routine procedures such as adenotonsillectomy should be admitted to a high-visibility bed in the hospital with continuous cardiac and oxygen saturation monitoring. Intraoperative use of steroids and postoperative placement of nasopharyngeal airways and tongue sutures for anterior traction may reduce the risk of airway compromise after surgery. Narcotics and sedatives should be used sparingly in severely obstructed children. Obese patients and those with reduced neuromuscular tone may benefit from airway support with positive airway pressure. In the most extreme cases, overnight endotracheal intubation may be desirable. If it is suspected that the airway may be difficult to reintubate should obstruction occur after extubation, the tube should be remove in the operating room setting.

3.2.2 NASAL AND NASOPHARYNGEAL OBSTRUCTION

SRBD due to nasal and nasopharyngeal masses is best addressed by removal of the mass. Depending on the pathology, the procedure may be as simple as a transoral, retropalatal approach for adenoidectomy or marsupialization of nasolacrimal duct cysts, or as complex as an anterior craniofacial approach for encephalocele. In most cases, microdebriders fitted with blades of appropriate size can be used to resect such lesions (see Adenotonsillectomy section below). Some nasal and nasopharyngeal neoplasms may require aggressive resection, as well as preoperative embolization (juvenile nasopharyngeal angiofibroma) or postoperative radiation therapy or chemotherapy (malignancies).

Choanal stenosis or atresia and stenosis of the piriform aperture are common causes of obstructive apnea in neonates. While unilateral disease is often well tolerated until school age years, bilateral cases usually require early intervention due to the dependence of neonates on nasal breathing. Affected infants present with cyclic cyanosis relieved by crying, and the diagnosis is further established by inability to pass a 6-French suction catheter through the nasopharynx. Respiratory distress can typically be relieved using an oropharyngeal airway; the diagnosis is then confirmed and characterized by CT scanning. Such babies should not otherwise leave an intensive care setting until a secure airway is established by tracheotomy or repair of the bony defect. Timing of surgery is controversial; early repair with avoidance of tracheotomy is always desirable, but children several weeks to several months old will better tolerate bleeding and will better accommodate instruments used in the nasal cavity.

While choanal atresia may be approached by either the transpalatal or the transnasal route, improvements in endoscopic and powered instrumentation have made the transnasal approach the first choice for most otolaryngologists. Our preferred approach is as follows.

1. Anatomy of the nasal cavity is confirmed endoscopically using a small rigid nasal endoscope. The mucosa overlying the atresia plate is injected with 1% lidocaine with 1:100,000 epinephrine and the nose is briefly packed with pledgets of oxymetazoline.
2. The patient’s head is placed in extension and a Malek mouth gag (Stryker-Leibinger; Kalamazoo, MI) suspended on a stack of towels is used to facilitate exposure of the nasopharynx. A 3-0 silk suture placed through the uvula is secured cranially outside the patient to improve the exposure.
3. A 120° rod lens telescope (Karl Storz; Culver City, CA) is placed in the oral cavity with the palate retracted to directly visualize the atresia plate(s) via the nasopharynx.
4. A 6-French Van Buren urethral sound is passed into the nasal cavity on one side. Contact between the sound and the atresia plate is confirmed endoscopically by visualizing the sound through the thin plate, or by observing mucosal movement if the plate is thicker.
5. The atresia plate is perforated with the sound (Fig. 63.1A), and the perforation is dilated as much as possible using progressively larger sounds. This procedure is duplicated on the opposite side.
6. A backbiting forceps is introduced into one side of the nose and passed closed through the perforated atresia plate. The forceps are then opened and used to excise the posterior portion of the vomer (Fig. 63.1B).
7. Once the vomer has been considerably reduced, the mouth gag is removed and the procedure is completed transnasally using a 0° telescope. A 2.9 mm or 3.5 mm microdebrider blade is used in oscillating mode to remove any loose or undesirable soft tissue or cartilage. If necessary, the microdebrider may also be fitted with a 2.9 mm round burr used at high speed to drill down any remaining bony prominences.
8. Mitomycin C, which has been reported to reduce the risk of restenosis, may be applied topically to the choanal mucosa at a concentration of 0.4 mg/ml.
9. Stenting of the choanae is not usually necessary, but may be considered in some cases. Our preference is to use individual endotracheal tube stents for each side of the nose, trimmed to keep one end just inside the nasal introitus and the other just beyond the choana. The tube length is measured and recorded so caregivers can suction the appropriate distance. The tubes are rotated to place the beveled end facing anteriorly; a 2-0 silk sutures is then placed transeptally between the tubes and an additional suture is placed through the inferior tip on each side, securing the tube sublabially.
image image

Fig. 63.1 Endoscopic transnasal repair of choanal atresia. Viewed through a 120° telescope in the oropharynx, the atretic plate is perforated with a Van Buren sound (A). After dilating the perforation to the largest sound, backbiting forceps are introduced transnasally and used to resect the nasopharyngeal end of the nasal septum (B). After initial resection of bone, the endoscope may be placed transnasally to remove bone with greater precision.

In cases of piriform aperture stenosis, the offending bone may be approached through a sublabial approach (Fig. 63.2), and the aperture is widened using the 2.9 mm round burr at high speed. Stents may be placed as in choanal atresia repair if desired.

image

Fig. 63.2 Transoral repair of piriform aperture stenosis. Piriform aperture is exposed by a sublabial approach. Intranasal degloving incisions may be added if necessary. A drill or microdebrider fitted with a small cutting burr is used to widen the aperture bilaterally.

Patients return to the office 2–4 weeks postoperatively for reassessment and stent removal if placed, and again 8 weeks postoperatively. Steroid-containing ototopical drops may be used to reduce the risk of infection and granulation tissue. Should respiratory distress return, a trip to the operating room for dilation and/or revision should be considered.

Restenosis is the most common complication of these procedures. Success rates (permanent patency) in recent studies are quoted as 78% to 95% with 1–3 year follow-up; number of required revisions is very variable.12,13

Nasopharyngeal stenosis, once a common complication of syphilis, may result as a complication of adenotonsillectomy, uvulopalatopharyngoplasty, or surgery for cleft palate or velopharyngeal insufficiency. This disorder often causes obstruction of the upper airway that is even more significant than the disorder the original surgery was intended to correct. Typically, cicatrix forms circumferentially in the velopharynx as a result of excessive removal of mucosa from opposing surfaces.

In mild cases, lysis of the scar with some combination of steroid injection, topical application of mitomycin C, and nasopharyngeal stenting may be sufficient to re-establish adequacy of the nasopharyngeal airway. However, frequently simple release of the scarred area results in recurrence, and treatment must therefore include the movement of fresh, well-vascularized tissue to cover the denuded bed. A variety of techniques has been recommended, including Z-plasty, laterally based pharyngeal flaps, other advancement and rotation flaps, and radial forearm and jejunal free flaps. In most cases, the unilateral laterally based pharyngeal flap described by Cotton14 results in an adequate nasopharyngeal airway without restenosis. The procedure is as follows (Fig. 63.3).

1. The pharynx is exposed using a tonsil/adenoid mouth gag of the surgeon’s choosing (Fig. 63.3A). A 3-0 silk suture is placed through the uvula for purposes of retraction. The pharyngeal wall is injected with 1% lidocaine with 1:100,000 epinephrine lateral to the remaining velopharyngeal port.
2. The stenosis is released using a scalpel and scissors if necessary (Fig. 63.3B). The incision is carried through the underlying muscle and as far lateral as possible.
3. Flaps are developed submuscularly superior, inferior, and lateral to the incision (Fig. 63.3C).
4. A laterally based posterior pharyngeal flap is incised including an inferior back cut. The flap is elevated with the underlying muscle (Fig. 63.3D and E).
5. The area denuded by release of the stenosis is covered by advancing the pharyngeal flap. Closure is performed with 4-0 Vicryl and chromic gut sutures (Fig. 63.3F).
6. The entire area is injected with triamcinolone 40 mg/ml to reduce the risk of restenosis. Application of mitomycin C may also be considered.
7. Stents are placed, consisting of soft nasopharyngeal airways, endotracheal tubes, or prefabricated prostheses. We prefer to leave the stents for 8 weeks or as long as tolerated, although the necessary duration of such stenting is controversial.
image

Fig. 63.3 Laterally based pharyngeal flap for correction of nasopharyngeal stenosis. A, The velopharyngeal port is circumferentially narrowed. B and C, A retraction suture is placed in the uvula and a lateral incision is made from velopharyngeal opening into lateral scar on one side and deepened. D, The mucosa is elevated from the scar inferolaterally; excess scar may be excised. A laterally based posterior pharyngeal flap is incised incorporating a back cut. E, The flap is elevated along with the underlying muscle. F, Points (A1) and (B1) are closed to points (A) and (B) respectively, covering the denuded area. (After Cotton RT, Nasopharyngeal stenosis. Arch Otolaryngol 1985;111:146–8, Copyrighted 1985, American Medical Association.)

In refractory cases, more distal flaps such as the facial artery myomucosal (FAMM) flap or the sternocleidomastoid myocutaneous flap may be necessary considerations. Patients should be followed for at least 12 months postoperatively for surveillance of restenosis and compromise of vocal resonance.

3.2.3 ADENOTONSILLAR HYPERPLASIA AND OROPHARYNGEAL OBSTRUCTION

Adenotonsillectomy is generally the first intervention considered for most patients with SRBD, providing they have at least mild adenotonsillar hyperplasia. Improvements in snoring and polysomnography may be anticipated postoperatively in such patients, including those in whom obesity exacerbates their airway obstruction.15–18 Improvement following adenotonsillar surgery has also been demonstrated in children with preoperative enuresis, orthodontic abnormalities, and behavioral issues prior to surgery. Validated surveys suggest an overall improvement in quality of life after adenotonsillectomy.19,20

Over the past century, there has been an evolution in tonsillectomy and adenoidectomy indications, techniques, and devices. In the age of ether anesthesia, clinicians emphasized expedience and efficiency at the expense of complete dissection of the tissues. As improvements in anesthesia permitted more methodical dissection, new techniques were developed in an effort to reduce pain and bleeding associated with the procedure. Several new devices for tonsillectomy and adenoidectomy have been proposed in recent years as technology has evolved.

With the report by Krespi and Ling of serial tonsillectomy with CO2 laser in the outpatient setting came the notion that partial tonsillectomy was safe and less painful than traditional tonsillectomy for patients with tonsil hyperplasia.21 It is theorized that the exposure of muscle resulting from removal of the tonsil capsule is the cause of pain associated with tonsillectomy, and that leaving some small portion of the tonsil behind may vastly diminish this sequela.22 Proposed many years ago, the technique had been abandoned due to the risk of tonsil regrowth at a time when most such procedures were performed for recurring infection. Initially studied using the CO2 laser, intracapsular tonsillectomy is now more commonly performed using the microdebrider given its greater efficiency and lower cost (Fig. 63.4). Randomized studies comparing microdebrider intracapsular tonsillectomy to complete electrocautery tonsillectomy generally suggest a modest advantage in pain reduction, particularly otalgia, and return to normal activity; other outcomes yielded less consistent results.23–26 The procedure involves a slight increase in duration and blood loss. Devices for traditional tonsillectomy developed over the last 20 years, such as the harmonic scalpel (Ethicon Endo-Surgery; Cincinnati, OH), radiofrequency devices (Somnoplasty, Somnus Medical Technologies, Sunnyvale, CA), and Coblation® (Fig. 63.5; ArthroCare Corp., Sunnyvale, CA) have been studied in small trials that suggest modest reduction in pain compared with electrocautery, with further decrease in postoperative pain when the tonsil is reduced rather than excised.

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Fig. 63.4 Power-assisted intracapsular tonsillectomy using a microdebrider. The microdebrider is used at 2000 rpm.

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Jul 24, 2016 | Posted by in General Dentistry | Comments Off on Management of sleep-related breathing disorders in children

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